where \(S_1\) , \(S_2\) , and \(S_{12}\)  are the entropies of the subsystems and the total system,
respectively. Recently, such definition of entropy shows exceptionally fascinating features with regards to the black holes thermodynamics and draws in a special accentuation in literature
[1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}.
